The half-wetted bearing. Part 2: Potential application in low load contacts

Abstract

In a companion paper (Part 1) a hydrodynamic lubrication model was developed to describe the flow and pressure in a bearing in which the lubricant has a no-slip boundary condition with one bearing surface but can slip against the other surface at a critical shear stress. This paper examines the current evidence for liquid slip at solid surfaces and outlines the problems inherent in the lubrication of low load contacts. The paper then shows that a bearing design in which one surface is very smooth and oleophobic, thereby allowing lubricant slip to occur, while the other surface is conventionally oleophilic, may provide a very low friction coefficient in low load conditions such as are present in microelectromechanical systems and hard disk drives.